Colorectal cancer may rise in women who have their ovaries removed, according to new research.

The development of colorectal cancer is influenced by hormonal factors, and removal of the ovaries alters a woman's sex hormone levels. Among 195,973 Swedish women who had undergone ovary removal between 1965 and 2011, there was a 30% increase in the rate of colorectal cancer compared with the general population. After accounting for various factors, women who had both ovaries removed had a 2.3-times higher risk of rectal cancer than those who had only one ovary removed.

"Colorectal cancer risk was increased after oophorectomy in both pre- and postmenopausal women. This emphasizes that prophylactic resection of normal ovaries should be reserved for women with a clear indication," said Dr. Josefin Segelman, lead author of the British Journal of Surgery study.

Article: Population-based analysis of colorectal cancer risk after oophorectomy, Segelman, J., Lindström, L., Frisell, J. and Lu, Y., British Journal of Surgery, doi: 10.1002/bjs.10143, published online 26 April 2016.